The present invention generally relates to the field of signal propagation. In particular, the present invention relates to a waveguide configuration for signal propagation in telecommunication devices.
Differences in voltage are central to the operation of virtually all electrical circuits. Differential signaling relates to a particular application of this general concept. Specifically, two signals are sent from one device as outputs. These two signals are received by a second device as inputs. The information contained within the signals is derived from the differences in voltage or current between them by the second device. This allows various external noise signals to be subtracted out when the inputs are processed. The differences in signals convey the information rather than one signal evaluated with respect to a ground. When transmitting at very high data rates, over long distances and through noisy environments, single-ended transmission is often inadequate. In these applications, differential data transmission offers superior performance.
The primary disadvantages of differential signaling result from the additional space, design complexity, and production costs association with increasing the number of pins, traces and tranceivers. These disadvanatges can limit the overall efficiency and suitability for a differential signaling system in different operating environments. Therefore a need exists for communication devices and differential signaling systems that maintain the advantages while reducing the inefficiencies associated with using differential based signaling techniques.
In one aspect, the invention relates to a waveguide structure for differential transmission lines including first, second, and third ground structures (e.g., ground planes) and first and second signal lines. The width of the first signal line and the separation between the first signal line and each of the first and second ground structures are sufficient to permit fabrication of a circuit element on the first signal line in some embodiments. In another aspect, the invention relates to providing complementary decoupled differential transmission line connections between signal transmission lines and optical-electronic receivers and demultiplexing device. In another aspect, the invention relates to connecting communication devices with an electrical ground (G) and signal (S) connections arranged in a G-S-G-S-G a configuration.
In one aspect, the invention relates to a waveguide structure for differential transmission lines. The waveguide structure includes a first ground structure, a first signal line, a second ground structure, a second signal line, a third ground structure. The first signal line is typically positioned adjacent and substantially parallel to the first ground structure. The second ground structure has a first separation distance from the first ground structure and is typically positioned adjacent and substantially parallel to the first signal line. The first signal line is typically positioned between both the first and second ground structures. The second signal line typically has a second separation distance from the first signal line and is positioned adjacent and substantially parallel to the second ground structure. The second ground structure is typically positioned between both the first and second signal lines. The third ground structure typically has a third separation distance from the second ground structure and is positioned adjacent and substantially parallel to the second signal line. The second signal line is typically positioned between both the second and third ground structures.
In one embodiment, the first signal line has a substantially constant width. The first and second signal lines have a substantially constant width in another embodiment. In another embodiment, the width of the first signal line and the separation distances are sufficiently sized to permit fabrication of a circuit element on the first signal line. In another embodiment, the width of the first and second signal lines and the separation distances are sufficiently sized to permit fabrication of a circuit element on the first signal line and second signal lines.
In another aspect, the invention relates to a differential transmission line system. The differential transmission line system includes a first communication device, a second communication device, and a differential signal lire. The first communication device typically has at least five pin inputs. The second communication device typically has at least five pin outputs. The differential signal line typically has at least ten contacts arranged in a decoupled configuration. The first and second communication devices are typically connected to the differential signal line in a differential decoupled configuration. In one embodiment, the differential transmission line system further comprises two signal lines and three ground strictures.
In another aspect, the invention relates to a waveguide structure for differential transmission lines. The waveguide structure typically includes at least two signal lines and a plurality of ground structures, wherein each signal line is adjacent to two ground structures.